Effects of silicon negative ion implantation in semi-insulating gallium arsenide

ABSTRACT

In the present work, effects of silicon negative ion implantation into semi-insulating gallium arsenide (GaAs) samples with fluences varying between 1?×?10¹⁵ and 4?×?10¹⁷?ions?cm^?2 at 100?keV have been described. Atomic force microscopic images obtained from samples implanted with fluence up to 1?×?10¹⁷?ion?cm^?2 showed the formation of GaAs clusters on the surface of the sample. The shape, size and density of these clusters were found to depend on ion fluence. Whereas sample implanted at higher fluence of 4?×?10¹⁷?ions?cm^?2 showed bump of arbitrary shapes due to cumulative effect of multiple silicon ion impact with GaAs on the same place. GXRD study revealed formation of silicon crystallites in the gallium arsenide sample after implantation. The silicon crystallite size estimated from the full width at half maxima of silicon (111) XRD peak using Debye-Scherrer formula was found to vary between 1.72 and 1.87?nm with respect to ion fluence. Hall measurement revealed the formation of n-type layer in gallium arsenide samples. The current–voltage measurement of the sample implanted with different fluences exhibited the diode like behavior.     

GaAs光生载流子动力学机制的超快光谱学分析

利用飞秒激光泵浦探测技术,通过改变光学参数,如中心波长、功率,分别对未故意掺杂高纯n型砷化镓的差分反射谱进行研究,进而分析室温下砷化镓光生载流子动力学过程.首先,当泵浦光功率恒为100mW,探测光功率恒为10mW时,随着中心波长的增大,差分反射率峰值随之增大,信噪比也随之增加.其次,通过拟合不同延迟时间下泵浦光功率和差分反射率的实验曲线,并和理论模型比较后发现,在一定范围内的泵浦功率和差分反射率呈线性相关,未故意掺杂高纯n型砷化镓的饱和载流子浓度为(3.590 1±0.310 3)×1017 cm~(-3).在此基础上,把光生载流子动力学过程分为3个过程:804±67fs的光激发过程、134~268fs的初始散射过程、1ps和3~6ps的复合过程.研究表明,差分反射率与探测功率不存在显著的依赖性,但差分反射谱的信噪比与探测功率存在相关性.     

Growth and impurity-trapping kinetics in sulfur-doped gallium arsenide epitaxy

Measurements have been made on the effects of crystallization conditions on the growth rates and electrophysical parameters for sulfur-doped epitaxial gallium arsenide films: gas speed, supersaturation, and deposition temperature. There is a correlation between the impurity concentration and the growth rate. The results are discussed from a model that incorporates interaction between impurity atoms and matrix ones.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 71–76, January, 1988.     

Behavior of copper in gallium arsenide with a high tellurium concentration

The electrophysical properties and cathode luminescence spectra of gallium arsenide with a high tellurium concentration (n = 2·10¹⁸ cm^–3) alloyed with copper are investigated under different diffusion conditions. Centers are determined from measurements of the Hall effect with an ionization energy of 0.190 ± 0.006 eV whose concentration does not depend on the arsenic vapor pressure (0.1 and 1 atm) and the cooling rate of the samples from the diffusion temperature. A band with h_m = 1.30–1.32 eV whose intensity depends on the cooling conditions of the samples was observed in the cathode luminescence spectra of these samples. The nature of the observed defects is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 93–99, July, 1979.In conclusion of this article the authors express their gratitude to L. K. Tarasova for preparation of the samples.     

n型砷化镓深能级发光的动力学分析

本文从实验上研究了n型砷化镓中深能级有关的阴极射线致发光的温度猝灭与激发强度的关系以及阴极射线致发光的瞬态特性。采用两种样品;在n型GaAs衬底上用MOCVD外延的n型GaAs（掺S）的样品和在此基础上800℃扩入放射性Cr51的样品。用SI阴极光电倍增管接收阴极射线致发光,利用光子计数和延迟符合技术进行测量。以单能级和双能级两种模型分别计算了发光的稳态强度和衰减动力学过程。     

Effect of gettering on the atomic structure of gallium arsenide

No changes in the lattice constant or standard parameters due to statistical displacements of atoms from their ideal positions at room temperature are revealed during a study of the atomic structure of gallium arsenide crystals gettered by yttrium. Nonetheless, the effect observed for conventional, ungettered crystals and associated with the influence of point defects on the phonon spectrum disappears.     

Variation of electron concentration in gallium arsenide due to irradiation by fast neutrons

The effects of irradiation by fast neutrons on gallium arsenide crystals with different degrees of initial perfection is investigated. It is shown that for relatively perfect, specially non-doped n-type crystals the degree of damage K is weakly dependent on the integrated radiative flux up to some critical flux determined by the initial current carrier concentration. The decrease in the rate of carrier removal in crystals with an elevated concentration of residual defects is due to the participation of the latter in the kinetics of defect formation. The initial rates of carrier removal are obtained in crystals grown by different methods.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 47–51, January, 1973.     

Galvanomagnetic and thermomagnetic effects in compensated gallium arsenide

The kinetic effects:-Hall effect, magnetoresistance, and Nernst-Ettinghausen effect-are examined in n-type gallium arsenide having a free electron concentration at room temperature of less than 10¹⁵ cm^–3.The work was directed toward determining the dominating scattering mechanism in compensated material.At low temperatures the scattering is predominately by impurity atoms and optical vibrations (optical phonons); at high temperatures, by acoustic phonons.With simultaneous scattering by thermal vibrations and impurity ions, for temperatures T > 300 ° K, the second mechanism plays the basic role in the longitudinal Nernst-Ettinghausen effect.     

Graphical method for determining the electrical parameters of epitaxial layers of n-type gallium arsenide and phosphide

The electrical parameters of epitaxial layers of n-type GaAs and GaP were determined by graphical analysis of the temperature dependence of the Hall coefficient with the help of the neutrality condition. The method is developed for application to both shallow and deep impurity levels.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 21–26, October, 1976.It is a genuine pleasure for the author to thank D. N. Nasledov and O. V. Emel'yanenko for interest and attention they have accorded this work, and R. K. Rad for supplying the gallium phosphide samples.     

A change in the electro-physical properties of narrow-band CdHgTe solid solutions acted upon by a volume discharge induced by an avalanche electron beam in the air at atmospheric pressure

The effect of a nanosecond volume discharge forming in an inhomogeneous electrical field at atmospheric pressure on the CdHgTe (MCT) epitaxial films of the p-type conduction with the hole concentration 2·10¹⁶ cm³ and mobility 500 cm²·V^–1·s^–1 is studied. The measurement of the electrophysical parameters of the MCT specimens upon irradiation shows that a layer exhibiting the n-type conduction is formed in the near-surface region of the epitaxial films. After 600 pulses and more, the thickness and the parameters of the layer are such that the measured field dependence of the Hall coefficient corresponds to the material of the n-type conduction. Analysis of the preliminary results reveals that the foregoing nanosecond volume discharge in the air at atmospheric pressure is promising for modification of electro-physical MCT properties.     

Development of n-type Te-doped GaSb substrates with low carrier concentration for FPA applications

Undoped GaSb is p-type with the residual acceptor concentration of about 1e17 cm⁻³ due to the gallium vacancies and gallium in antimony site. Counter-doping of GaSb with low level of Te can reduce the net carrier concentration resulting in higher optical transparency in a broad IR spectral range. In this work, the carrier concentration, mobility and sheet resistance of n-type and p-type Te-doped GaSb substrates were measured using Hall method at 300 K and 77 K. The Hall carrier concentration data at 300 K were correlated with the absorption coefficients of GaSb in the IR spectral range. An empirical relationship between these values was established. Based on this correlation, we discuss application of FTIR spectroscopy for non-destructive optical screening of the substrates that allows construction of the carrier concentration distribution map across GaSb wafers. Investigations of the electronic properties of the low-doped p-type and n-type GaSb substrates upon cooling down to 77 K indicate the reduction of the hole carrier concentration background for both GaSb types. This is evident from the decrease in the Hall-measured carrier concentration for p-type GaSb. For n-type GaSb, an increase in the carrier concentration is observed due to the reduction of the hole carrier concentration background.     

Imaging the edge channel structure in a quantum Hall device

In a magnetically quantised two dimensional electron gas (2DEG) of finite dimension, the Landau levels bend up at the boundaries due to the confining potential. Edge channels are formed where these intersect the Fermi level. We have used laser imaging with a spatial resolution of 5 μm to investigate the edge channel structure in a gallium arsenide Hall bar at temperatures between 1.5 K and 150 mK. The beam from an Ar⁺ laser is focused to a small spot on the top surface of the device and the induced Hall photovoltage is measured as a function of the spot position. The size of the photovoltage depends on the potential profile in the device and, at integer Landau level filling factors, is a maximum at the edges. In our device the edge regions turn out to be very wide compared to the magnetic length.     

Influence of microwave treatment on the electrophysical characteristics of technically important semiconductors and surface-barrier structures

An investigation is made of changes in the electrophysical parameters of narrow-gap (Cd_xHg_1−x Te x=0.22–0.24) and wide-gap (gallium arsenide, indium and gallium phosphides) semiconductor materials and Schottky-barrier diode structures based on these materials, stimulated by microwave electromagnetic radiation. It is shown that the parameters of materials and device structures may be improved by defect gettering. An analysis is made of possible mechanisms for the interaction between microwave radiation and the objects being studied. Zh. Tekh. Fiz. 68, 49–53 (December 1998)     

Plasma reflection in gallium arsenide

Procedures recently proposed for determining electrophysical parameters of highly doped semiconductors from the IR reflection spectra are analyzed. The case of n-type GaAs is discussed. Optical and Hall measurements have been carried out for a few samples, and it has been found that the electron density determined from the optical measurements is in good agreement with the Hall values, while the mobilities may differ significantly. It is concluded that mechanical polishing causes problems.Translated from Izvestiya VUZ. Fizika, No. 10, pp. 65–69, October, 1969.     

Size-effect parameters for thin films of the aluminium group metals

Measurements were made of the sheet resistivity and Hall voltage of vacuum-deposited polycrystalline aluminium, gallium, indium, and thallium films 500–5000 Å thick, cooled to 4.2°K. The results fit a low-temperature form of the Sondheimer size-effect relations, and may then be used to determine the electron-transport parameters.     

Effect of hydrogen on the current-voltage characteristics of tunneling mis diodes based on gallium arsenide

Results are presented for experimental studies of the static current-voltage characteristics of tunneling MIS diodes based on n-type gallium arsenide. It is shown that the forward branch of the current-voltage characteristics can be used to determine the dependence of the surface potential at the dielectric-semiconductor interface on the voltage and the distribution of the surface state density over energy in the forbidden band. The results of studies of these dependences for diodes prepared by thermal annealing at various temperatures are given. The possible causes of changes in the forward and reverse current, and the dependence of the surface potential on the voltage and distribution of surface state density in energy under the action on the diodes of a gaseous mixture containing hydrogen are analyzed. V. D. Kuznetsov Siberian Physicotechnical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 69–83, January, 1998.     

Degradation of gallium arsenide under irradiation with an excimer laser

The results of a study of degradation of the surface of gallium arsenide resulting from irradiation with a power excimer laser at power densities ranging from the threshold power to the power level causing local melting of the surface are presented. Two degradation mechanisms have been identified, one of which causes the formation of a thin near-surface layer of modified nonstoichimetric gallium arsenide at a power level higher than 1×10⁷ W/cm² and the other of which causes the formation of a separate gallium phase. The formation of the separate gallium phase can be produced either by a single pulse of laser radiation with a power density exceeding 2.7×10¹¹ W/cm² or by a few less powerful pulses. An empirical relationship has been established between the power density and the number of pulses causing the formation of the separate gallium phase. It has also been established that as a result of laser irradiation at the boundary of “cold” and “hot” gallium arsenide, periodically ordered defects in the form of blocks aligned along the [100] directions emerge.     

Hall effect and photoluminescence in vapor-phase epitaxial gallium arsenide heavily doped with sulfur

Hall mobility and photoluminescence have been studied in degenerate sulfur doped gallium arsenide vapor-epitaxial films. The results are in agreement with the measurements on tellurium and selenium doped GaAs made earlier by several investigators.     

Hall mobility of amorphous Ge2Sb2Te5

The electrical conductivity, Seebeck coefficient, and Hall coefficient of three-micron-thick films of amorphous Ge₂Sb₂Te₅ have been measured as functions of temperature from room temperature down to as low as 200 K. The electrical conductivity manifests an Arrhenius behavior. The Seebeck coefficient is p-type with behavior indicative of multi-band transport. The Hall mobility is n-type and low (near 0.07 cm²/V s at room temperature).     

磷砷化镓黄色发光二极管

采用掺氨砷压法在磷化镓衬底上外延生长掺碲n型的GaAs0.15P0.85:N/GaP材料,制成磷砷化镓黄色发光二极管,测量了其光学和电学性能.讨论了影响器件发光效率的因素.